Exterior coatings for golf balls

ABSTRACT

Improved golf ball exterior coatings which are used to create an extremely uniform hydrophobic or hydrophilic exterior surface on the golf ball. When the surface of the golf ball is hydrophobic, it tends to repel water, and this reduces drag on the golf ball surface as the golf ball travels through the air. When the surface of the golf ball is hydrophilic, the surface of the golf ball wets uniformly and the ball rolls straighter on a wet green, as the forces acting on the ball are more uniform. The hydrophobic or hydrophilic exterior coating is applied to the golf ball using vapor-phase deposition in instances where strict control over coating thickness uniformity, and/or reduced surface roughness is desired.

This application is related to a series of patent applicationspertaining to the application of thin film coatings on varioussubstrates, particularly including U.S. patent application Ser. No.10/862,047, filed Jun. 4, 2004, and entitled “Controlled Deposition ofSilicon-Containing Coatings Adhered by an Oxide Layer”; and, U.S. patentapplication Ser. No. 10/996,520, filed Nov. 19, 2004, and entitled“Controlled Vapor Deposition of Multilayered Coatings Adhered by anOxide Layer”. Both of these applications are hereby incorporated byreference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to golf balls coated with exterior thinfilm coatings which affect the performance of the golf ball during play.

2. Brief Description of the Background Art

This section describes background subject matter related to theinvention, with the purpose of aiding one skilled in the art to betterunderstand the disclosure of the invention. There is no intention,either express or implied, that the background art discussed in thissection legally constitutes prior art.

A multitude of studies have been conducted with respect to aspects ofthe composition and shape of the golf ball which affect it'sperformance. One of the more interesting is an article entitled “A St.Mary's Project: The Aerodynamics of Golf Ball Flight”, by Kevin E.Warring, Department of Physics, St. Mary's College of Maryland, St.Mary's City, Md., published in the Spring of 2003. This article providesan introduction to Fluid Dynamics which affect golf ball flight; thedimpled golf ball and drag; the Magnus force (a major force acting onthe golf ball due to its spin); and, the modeling of golf ball flight ingeneral. The author explains how to predict the trajectory of a golfball give its initial launch angle, velocity and spin rate. The articlediscusses applications of the principles discussed to golf ball design.

A web site at www.indoindians.com/golfbcore.htm, in January 2006contained an article titled “Dimples Drive Drag Out of Golf Balls”, thisarticle explains that at airspeed, sticky air slows a ball downsubstantially. The ball is said to get wet as it travels through air, sothat the surface of the ball is referred to as a “wetted surface”. Theuse of dimples on the ball surface is said to make air molecules in theboundary layer adjacent the golf ball surface tumble, so that theboundary layer becomes turbulent. The article teaches that when theboundary layer is turbulent and thin, the ball loses less energy to thefree stream air and the drag on the ball is lower. In addition to thediscussion of the golf ball in flight, there is a presentation aboutwhat happens to a golf ball after it sits at the bottom of a pond. Astudy was conducted with respect to balls which were permitted to sit inwater at temperatures ranging from 36 to 70° F. for a period of sixmonths. The balls were tested using a robotic hitting machine. Theaverage carry, and roll for the new balls was about 251 yards. Theaverage carry and roll for balls that had been in the water for eightdays was about 236 yards. After three months, the average carry and rollhad decreased to about 226 yards, and after six months, the averagecarry and roll was about 225 yards. This may be viewed as a six yardloss of distance after eight days, a 12 yard loss after three months,and a 15 yard loss after six months.

U.S. Pat. No. 6,509,410 to Ohira et al., issued Jan. 21, 2003, describesan aqueous coating composition for a golf ball. The aqueous coatingcomposition is said to form a high crosslink density owing to the highhydroxyl value, to contain. The coating produced is said to have highimpact resistance, abrasion resistance, contamination resistance, etc.which are equivalent to films produced from organic solvent typecoatings. The coating formed is said to be free from cracking or filmpeeling when hit by a golf club; is said to be low in scratch, abrasionand contamination with grass sap, and is said to provide a coated golfball which retains gloss and fine appearance.

U.S. Pat. No. 6,806,347 to Hogge et al., issued Oct. 19, 2004, describesgolf balls with a thin moisture vapor barrier layer. The golf ballcomprises a core, a cover, and at least one water vapor barrier layer,where the water vapor barrier layer comprises at least one layer formedfrom poly-para-xylene and its derivatives. The patent discusses WVB(water vapor barrier) layers and WVT (water vapor transmission) rates.The thin moisture vapor barrier layer described, which is formed frompoly-para-xylene, and its derivatives. Parylenes are selected asmaterials of choice to form the thin WVB layers, particularly when theparylene is halogenated to include a group VIIA element. The group VIIAelement may be fluorine, chlorine, bromine, iodine, or astatine. Thepreferred element is chlorine. The WVB layer comprising parylenes istypically formed using vapor deposition polymerization at a steady rate.The thickness of the parylene-based WVB layer is said to be controllableat any desired nominal thickness because the WVB layer is formed viavapor deposition polymerization at a steady rate. Thickness of the layercommonly ranges from about 0.025 μm to about 75 μm. The thickness ispreferably from about 1 μm to about 25 μm, and most preferably fromabout 3 μm to about 10 μm. One or more of the thin WVB layers may bedisposed between the golf ball core and the cover. Substrates such asgolf ball cores and golf ball sub-assemblies are prepared for parylenecoating by cleaning off oils and other surface contaminants. Thesubstrate may then be pre-treated by application of a “multi-molecular”layer of organosilane to promote adhesion of the parylene coating. Theparylene precursor, a granular white powder, is vaporized at about 150°and 1.0 Torr vacuum in a vaporizer chamber. The resulting gaseous formof stable dimeric di-para-xylene is further heated in a pyrolysischamber to about 680° C. at about 0.5 Torr vacuum, to directly break thetwo methylene-methylene bonds and yield stable monomeric diradicals,para-xylene, also in gaseous form. The monomer is then sent to thedeposition chamber at ambient temperature and about 0.1 torr vacuum. Theresulting parylene coating is said to be very stable and extremelyresistant to moisture vapor permeation, chemical attacks and hydrolyticbreakdown.

U.S. Patent Application Publication No. US 2005/0009638, of Wu et al.,published Jan. 13, 2005, describes golf ball layers formed ofpolyurethane-based and polyurea-based compositions incorporating blockcopolymers. The golf balls typically comprise three layers. The corelayer is typically formed from a thermoset material or a thermoplasticmaterial. When the cores are formed from a thermoset material,compression molding is typically used to form the core. When the core isthermoplastic, the cores may be injection molded. The intermediate layermay be formed from any suitable method known to those of ordinary skillin the art, and may be formed by blow molding. The outer layer isgenerally a dimpled cover layer formed by injection molding, compressionmolding, casting, vacuum forming, powder coating, and the like.

The published application discusses a large amount of material, however,based on the claims, the focus appears to be a golf ball comprising acore and a cover, where the cover is formed from a compositioncomprising a prepolymer and a curing agent, where the prepolymerincludes a first prepolymer and a block copolymer having functionalgroups at each terminal end, where the composition comprises ahydrophobic A_(x)-B_(y)-A_(z) block capped between iso-cyanate groups,wherein x, y, and z are independently 1 or greater. The block istypically a styrene-butadiene block. The functional groups at theterminal ends of the block are selected from groups such as hydroxygroups, amino groups, thiol groups, epoxy groups, anhydride groups andcombinations of these. The terminal groups are designed to provide acover which is water resistant. The cover material was molded onto woundcores, and a “conventional coating” was applied over the cover. The golfballs were incubated in a 50% relative humidity and 72° F. environmentalchamber and then were removed, weighed and measured. Subsequently theballs were subjected to 100 percent relative humidity at 72° F. and thenweighed and measured. Balls with the water resistant cover were shown tohave picked up much less weight and to have incurred less size gain dueto the exposure to the high relative humidity than a control ball.

When the layer or coating of material applied to the golf ball is anexterior coating, which will experience wear due to mechanical contactor will experience fluid flow over the coated surface, it is helpful tohave the coating chemically bonded directly to the substrate surface viachemical reaction of active species which are present in the coatingreactants/materials with active species on the underlying substratesurface.

For purposes of illustrating methods of coating formation where vaporousand liquid precursors are used to deposit a coating on a substrate,applicants would like to mention the following publications and patentswhich relate to methods of coating formation, for purposes ofillustration. Most of the background information provided is withrespect to various chlorosilane-based precursors; however it is notintended that the present invention be limited to this class ofprecursor materials.

In an article by Barry Arkles entitled “Tailoring surfaces withsilanes”, published in CHEMTECH, in December of 1977, pages 766-777, theauthor describes the use of organo silanes to form coatings which impartdesired functional characteristics to an underlying oxide-containingsurface. In particular, the organo silane is represented asR_(n)SiX_((4-n)) where X is a hydrolyzable group, typically halogen,alkoxy, acyloxy, or amine. Following hydrolysis, a reactive silanolgroup is said to be formed which can condense with other silanol groups,for example, those on the surface of siliceous fillers, to form siloxanelinkages. Stable condensation products are said to be formed with otheroxides in addition to silicon oxide, such as oxides of aluminum,zirconium, tin, titanium, and nickel. The R group is said to be anonhydrolyzable organic radical that may possess functionality thatimparts desired characteristics. The article also discusses reactivetetra-substituted silanes which can be fully substituted by hydrolyzablegroups and how the silicic acid which is formed from such substitutedsilanes readily forms polymers such as silica gel, quartz, or silicatesby condensation of the silanol groups or reaction of silicate ions.Tetrachlorosilane is mentioned as being of commercial importance sinceit can be hydrolyzed in the vapor phase to form amorphous fumed silica.

The article by Dr. Arkles shows how a substrate with hydroxyl groups onits surface can be reacted with a condensation product of anorganosilane to provide chemical bonding to the substrate surface. Thereactions are generally discussed and, with the exception of theformation of amorphous fumed silica, the reactions are between a liquidprecursor and a substrate having hydroxyl groups on its surface. Anumber of different applications and potential applications arediscussed.

In an article entitled “Organized Monolayers by Adsorption. 1. Formationand Structure of Oleophobic Mixed Monolayers on Solid Surfaces”,published in the Journal of the American Chemical Society, Jan. 2, 1980,pp. 92-98, Jacob Sagiv discussed the possibility of producing oleophobicmonolayers containing more than one component (mixed monolayers). Thearticle is said to show that homogeneous mixed monolayers containingcomponents which are very different in their properties and molecularshape may be easily formed on various solid polar substrates byadsorption from organic solutions. Irreversible adsorption is said to beachieved through covalent bonding of active silane molecules to thesurface of the substrate.

In June of 1991, D. J. Ehrlich and J. Melngailis published an articleentitled “Fast room-temperature growth of SiO₂ films by molecular-layerdosing” in Applied Physics Letters 58 (23), pp. 2675-2677. The authorsdescribe a molecular-layer dosing technique for room-temperature growthof α-SiO₂ thin films, which growth is based on the reaction of H₂O andSiCl₄ adsorbates. The reaction is catalyzed by the hydrated SiO₂ growthsurface, and requires a specific surface phase of hydrogen-bonded water.Thicknesses of the films is said to be controlled to molecular-layerprecision; alternatively, fast conformal growth to rates exceeding 100nm/min is said to be achieved by slight depression of the substratetemperature below room temperature. Potential applications such astrench filling for integrated circuits and hermetic ultrathin layers formultilayer photoresists are mentioned. Excimer-laser-induced surfacemodification is said to permit projection-patterned selective-areagrowth on silicon.

An article entitled “Atomic Layer Growth of SiO₂ on Si(100) Using TheSequential Deposition of SiCl₄ and H₂O” by Sneh et al. in Mat. Res. Soc.Symp. Proc. Vol 334, 1994, pp. 25-30, describes a study in which SiO₂thin films were said to be deposited on Si(100) with atomic layercontrol at 600° K. (≅327° C.) and at pressures in the range of 1 to 50Torr using chemical vapor deposition (CVD).

In U.S. Pat. No. 5,372,851, issued to Ogawa et al. on Dec. 13, 1995, amethod of manufacturing a chemically adsorbed film is described. Inparticular a chemically adsorbed film is said to be formed on any typeof substrate in a short time by chemically adsorbing a chlorosilanebased surface active-agent in a gas phase on the surface of a substratehaving active hydrogen groups. The basic reaction by which achlorosilane is attached to a surface with hydroxyl groups present onthe surface is basically the same as described in other articlesdiscussed above. In a preferred embodiment, a chlorosilane basedadsorbent or an alkoxyl-silane based adsorbent is used as thesilane-based surface adsorbent, where the silane-based adsorbent has areactive silyl group at one end and a condensation reaction is initiatedin the gas phase atmosphere. A dehydrochlorination reaction or ade-alcohol reaction is carried out as the condensation reaction. Afterthe dehydrochlorination reaction, the unreacted chlorosilane-basedadsorbent on the surface of the substrate is washed with a non-aqueoussolution and then the adsorbed material is reacted with aqueous solutionto form a monomolecular adsorbed film.

In an article entitled “SiO₂ Chemical Vapor Deposition at RoomTemperature Using SiCl₄ and H₂O with an NH₃ Catalyst”, by J. W. Klausand S. M. George in the Journal of the Electrochemical Society, 147 (7)2658-2664, 2000, the authors describe the deposition of silicon dioxidefilms at room temperature using a catalyzed chemical vapor depositionreaction. The NH₃ (ammonia) catalyst is said to lower the requiredtemperature for SiO₂ CVD from greater than 900° K. to about 313-333° K.

U.S. Patent Publication No. US 2002/0065663 A1, published on May 30,2002, and titled “Highly Durable Hydrophobic Coatings And Methods”,describes substrates which have a hydrophobic surface coating comprisedof the reaction products of a chlorosilyl group containing compound andan alkylsilane. The substrate over which the coating is applied ispreferably glass. In one embodiment, a silicon oxide anchor layer orhybrid organo-silicon oxide anchor layer is formed from a humidifiedreaction product of silicon tetrachloride or trichloromethylsilanevapors at atmospheric pressure. Application of the oxide anchor layeris, followed by the vapor-deposition of a chloroalkylsilane. The siliconoxide anchor layer is said to advantageously have a root mean squaresurface (RMS) roughness of less than about 6.0 nm, preferably less thanabout 5.0 nm and a low haze value of less than about 3.0%. The RMSsurface roughness of the silicon oxide layer is preferably said to begreater than about 4 nm, to improve adhesion. However, too great an RMSsurface area is said to result in large surface peaks, widely spacedapart, which begins to diminish the desirable surface area forsubsequent reaction with the chloroalkylsilane by vapor deposition. Toosmall an RMS surface is said to result in the surface being too smooth,that is to say an insufficient increase in the surface area/orinsufficient depth of the surface peaks and valleys on the surface.

Simultaneous vapor deposition of silicon tetrachloride anddimethyldichlorosilane onto a glass substrate is said to result in ahydrophobic coating comprised of cross-linked polydimethylsiloxane whichmay then be capped with a fluoroalkylsilane (to provide hydrophobicity).The substrate is said to be glass or a silicon oxide anchor layerdeposited on a surface prior to deposition of the cross-linkedpolydimethylsiloxane. The substrates are cleaned thoroughly and rinsedprior to being placed in the reaction chamber.

U.S. Pat. No. 5,576,247 to Yano et al., issued Nov. 19, 1996, entitled:“Thin layer forming method where hydrophobic molecular layers preventinga BPSG layer from absorbing moisture”.

Some of the various methods useful in applying layers and coatings to asubstrate have been described above. There are numerous other patentsand publications which relate to the deposition of functional coatingson substrates, but which appear to be more distantly related to thepresent invention. To provide a monolayer or a few layers of afunctional coating on a substrate surface so that the surface willexhibit particular functional properties it is necessary to tailor thecoating precisely. Without precise control of the deposition process,the coating may lack thickness uniformity and surface coverage. Thecoating may vary in chemical composition across the surface of thesubstrate, affecting uniformity of behavior of the surface. The presenceof non-uniformities may result in functional discontinuities and defectson the coated substrate surface which are unacceptable for the intendedapplication of the coated substrate.

U.S. patent application Ser. No. 10/759,857 of the present applicantsdescribes processing apparatus which can provide specificallycontrolled, accurate delivery of precise quantities of reactants to theprocess chamber, as a means of improving control over a coatingdeposition process. The subject matter of the '857 application is herebyincorporated by reference in its entirety.

The present application is related to an exterior coating forapplication to a golf ball. In a first instance the exterior coatingprovides a hydrophobic surface on the golf ball. In a second instancethe exterior coating provides a hydrophilic surface on the golf ball.Use of the disclosed method of coating deposition described belowenables the precise control of process conditions during deposition ofthe coatings, the coatings exhibit a uniform functionality over theentire golf ball surface, a nanometer scale functionality which issuperior to previous golf ball coatings. Due to the accurate delivery ofquantities of reactive materials and the conditions under which thematerials can be processed, the cost of coating application is greatlyreduced as well.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional schematic of one embodiment of the kindof an apparatus which can be used to carry out a vapor deposition of acoating in accordance with the method of the present invention.

FIG. 2 is a schematic which shows the reaction mechanism wheretetrachlorosilane and water are reacted with a substrate which exhibitsactive hydroxyl groups on the substrate surface, to form a silicon oxidelayer on the surface of the substrate.

FIG. 3 shows a series of water contact angles measured for variouscoated surfaces. The higher the contact angle, the higher thehydrophobicity of the coating surface.

FIG. 4A shows a three dimensional schematic of film thickness of asilicon oxide bonding layer coating deposited on a silicon surface as afunction of the partial pressure of silicon tetrachloride and thepartial pressure of water vapor present in the process chamber duringdeposition of the silicon oxide coating, where the time period thesilicon substrate was exposed to the coating precursors was four minutesafter completion of addition of all precursor materials.

FIG. 4B shows a three dimensional schematic of film thickness of thesilicon oxide bonding layer illustrated in FIG. 4A as a function of thewater vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials.

FIG. 4C shows a three dimensional schematic of film thickness of thesilicon oxide bonding layer illustrated in FIG. 4A as a function of thesilicon tetrachloride partial pressure and the time period the substratewas exposed to the coating precursors after completion of addition ofall precursor materials.

FIG. 5A shows a three dimensional schematic of film roughness in RMS nmof a silicon oxide bonding layer coating deposited on a silicon surfaceas a function of the partial pressure of silicon tetrachloride and thepartial pressure of water vapor present in the process chamber duringdeposition of the silicon oxide coating, where the time period thesilicon substrate was exposed to the coating precursors was four minutesafter completion of addition of all precursor materials.

FIG. 5B shows a three dimensional schematic of film roughness in RMS nmof the silicon oxide bonding layer illustrated in FIG. 5A as a functionof the water vapor partial pressure and the time period the substratewas exposed to the coating precursors after completion of addition ofall precursor materials.

FIG. 5C shows a three dimensional schematic of film roughness in RMS nmof the silicon oxide bonding layer illustrated in FIG. 5A as a functionof the silicon tetrachloride partial pressure and the time period thesubstrate was exposed to the coating precursors after completion ofaddition of all precursor materials.

FIG. 6 illustrates the minimal thickness of oxide-based bonding layerwhich is required to provide adhesion of an organic-based layer, as afunction of the initial substrate material, when the organic-based layeris one where the end or the organic-based layer which bonds to theoxide-based bonding layer is a silane and where the end of theorganic-based layer which does not bond to the oxide-based bonding layerprovides a hydrophobic surface. When the oxide thickness is adequate toprovide uniform attachment of the organic-based layer, the contact angleon the substrate surface increases to about 110 degrees or greater.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

We have developed improved golf ball exterior coatings which are used tocreate an extremely uniform (to within about ±2 nm) hydrophobic orhydrophilic exterior coating on a golf ball surface. When the surface ofthe golf ball is hydrophobic, it tends to repel water, and this reducesthe condensation of moisture present in the air onto the golf ball asthe golf ball travels through the air. As a result, the amount of dragon the golf ball is reduced, increasing the distance of travel which canbe achieved in a given stroke. When a golf ball is rolling across grasswhich exhibits a wet surface, for example dew (condensation on thesurface of the grass) is present, or there are wet spots on the grass,there is an advantage when the golf ball has an exterior surface whichis hydrophilic. The hydrophilic surface of the golf ball wets uniformlyand the ball rolls straighter, as the forces acting on the ball are moreuniform. Putting will be better using the golf ball with the hydrophilicsurface. When the golf ball is in a sand trap or is on a dry grasssurface where some debris is present, there is an advantage in using agolf ball with a hydrophobic surface which will not stick to the sand orto debris present on the grass surface. The ball tends to stay cleaneras it rolls over the green, improving the directionality of travel ofthe ball during putting, for example.

The hydrophobic or hydrophilic exterior coating is applied to the golfball using vapor-phase deposition in instances where strict control overcoating thickness uniformity, and/or reduced surface roughness isdesired. The coating formation method typically employs a batch-likeaddition and mixing of all of the reactants to be consumed in a givenprocess step, whether that step is one in a series of steps or is thesole step in a coating formation process. In some instances, the coatingformation process may include a number of individual steps whererepetitive reactive processes are carried out in each individual step.The apparatus used to carry out the method provides for the addition ofa precise amount of each of the reactants to be consumed in a singlereaction step of the coating formation process. The apparatus mayprovide for precise addition of quantities of different combinations ofreactants during each individual step when there are a series ofdifferent individual steps in the coating formation process.

In addition to the control over the amount of reactants added to theprocess chamber, the present invention requires precise control over thecleanliness of the substrate, the order of reactant(s) introduction, thetotal pressure (which is typically less than atmospheric pressure) inthe process chamber, the partial vapor pressure of each vaporouscomponent present in the process chamber, and the temperature of thesubstrate and chamber walls. The control over this combination ofvariables determines the deposition rate and properties of the depositedlayers. By varying these process parameters, we control the amount ofthe reactants available, the density of reaction sites, and the filmgrowth rate, which is the result of the balance of the competitiveadsorption and desorption processes on the substrate surface, as well asany gas phase reactions.

The coating deposition process is carried out in a vacuum chamber wherethe total pressure is lower than atmospheric pressure and the partialpressure of each vaporous component making up the reactive mixture isspecifically controlled so that formation and attachment of molecules ona substrate surface are well controlled processes that can take place ina predictable manner, without starving the reaction from any of theprecursors.

In some instances, where it is desired to have a particularly uniformgrowth of the composition across the coating surface, or a variablecomposition across the thickness of a multi-layered coating, more thanone batch of reactants may be charged to the process chamber duringformation of the coating.

The coatings formed by the method of the invention are sufficientlycontrolled that the surface roughness of the coating in terms of RMS istypically less than about 15 nm, and is typically in the range of about3 nm to 10 nm. However, although the coating itself does not createsignificant roughness on a surface, the roughness of a substrate surfacetends to be replicated in the coated substrate surface. Thus, theroughness on the surface of a golf ball is likely to be in the range ofthe roughness of the outer layer (typically the cover layer) of the golfball over which the coating is applied.

The golf ball exterior coating may be a single layer. For example, anoxide layer is generally hydrophilic in nature, and variousfunctionalized organic materials exhibit a hydrophobic chemical group atone end of the molecule which can provide a hydrophobic surface on thegolf ball. Frequently, however, the exterior coating includes at leasttwo layers, where the first layer applied over the golf ball surface isan adhesion promoting layer to ensure bonding of a second layer whichpresents the hydrophilic or hydrophobic properties on the surface of thegolf ball. The adhesion promoting layer is required on polymericsurfaces of the kind which are known in the industry for use as an outercover of a golf ball. Subsequently, this adhesion promoting layer isreferred to as a “bonding” layer, for general purposes of description.

An oxide layer has been demonstrated to work well as a bonding layer onthe golf ball surface. By controlling the precise thickness, chemical,and structural composition of an oxide layer on a polymeric substrate,for example, we are able to tailor the oxide layer surfacecharacteristics and thickness to meet the requirements for air flow overa golf ball surface. When the golf ball exterior coating is ahydrophobic coating, a bonding layer of oxide is applied first, followedby a layer of organic material which comprises organic molecules whichbond to the oxide layer at one end and presents a hydrophobiccomposition at the other end of the molecule. The hydrophobic surfacelayer applied over the bonding layer is typically a self-alignedmonolayer coating (SAM), which is self limiting in thickness. When thegolf ball exterior coating is a hydrophilic coating, a thick oxide layeralone may be used to provide the hydrophilic surface, as mentionedabove. In the alternative, a layer of hydrophilic organic material whichcomprises organic molecules which bond to the oxide layer at one end andpresent a hydrophilic composition at the other end of the molecule maybe used over the oxide surface. An example, not by way of limitation,such an organic material is polyethylene glycol, which is commonlyreferred to as PEG or as polyethylene oxide (PEO). The precursor forformation of the hydrophilic organic material is typically afunctionalized silane containing PEO/PEG groups, where the silane reactswith the oxide bonding layer. The silane functionalized PEG may be usedto create a monolayer, a self-aligned monolayer, or a polymerizedcross-linked layer. Several coating layers of PEG may be applied toincrease the thickness of the PEG layer, so long as the golf balls arenot exposed to ambient contaminants between coating steps. The coverageand functionality of the exterior coated surface on the golf ball,whether hydrophobic or hydrophilic, can be controlled on a nanometerscale.

With reference to chlorosilane-based coating systems of the kinddescribed in the Background Art section of this application, forexample, and not by way of limitation, the degree of hydrophobicity ofthe substrate after deposition of an oxide bonding layer and afterdeposition of an overlying silane-based polymeric material whichpresents a hydrophobic surface can be uniformly controlled over thesubstrate surface. By controlling a deposited bonding layer (forexample) surface coverage and roughness in a uniform manner (as afunction of oxide deposition parameters, for example and not by way oflimitation), we are able to control the concentration of OH reactivespecies on the substrate surface. This, in turn, controls the density ofreaction sites needed for subsequent deposition of a silane-basedpolymeric coating which provides an exterior hydrophobic surface.Control of the substrate surface active site density enables uniformgrowth and application of high density SAMS.

Another important aspect of the present invention is the surfacepreparation of the substrate prior to initiation of any exterior coatingdeposition reaction on the substrate surface. For experimental purposes,we applied exterior coatings to golf balls having a cover layer of anionomer, for example and not by way of limitation. The ionomer was asodium or zinc salt of copolymers derived from ethylene and methacrylicacid. A golf ball surface, typically a cover layer, may be formed frommaterials in addition to ionomers. Such additional materials maycomprise polystyrene, polybutadiene, isoprene, polyurea, polyurethane,poly-para-xylene, poly-chloro-para-xylene, poly-dichloro-para-xylene,polyvinylidene chloride, polyvinylchloride, polyvinylchloride,polyacrylonitrile, fluorohalocarbons, fluorinated ethylene propylenecopolymer, polytetrafluoroethylene, polyvanilidine fluoride, polyvinylfluoride, perfluoroalkoxy resins, polyethylene, polyethyleneterephthalate, polypropylene high density polyethylene, polyimide,polyamide, acrylic, and combinations thereof.

The surface of the golf balls exhibiting an ionomer cover layer wasinitially cleaned using isopropyl alcohol to remove any oils or greasethat might have been present on the ball surface. Other commonlyavailable solvents used for surface cleaning of plastic materialssimilar to ionomers may be used to remove oils or grease present on golfball cover surfaces prior to application of an exterior surface coatingover the cover.

Subsequent to the solvent wipe with isopropyl alcohol, the golf ballsurfaces were treated with gentle, non-bombarding oxygen-containingplasmas, to further remove organic contaminants. The oxide layer createdover a plasma-treated polymeric substrate may comprise aluminum oxide,titanium oxide, or silicon oxide, by way of example and not by way oflimitation. When the oxide layer is aluminum or titanium oxide, anauxiliary process chamber (to the process chamber described herein) maybe used to create this oxide layer. When the oxide layer is a siliconoxide layer, the silicon oxide layer may be applied in the sameprocessing chamber in which the subsequent deposition of asilane-functionalized external layer is carried out. It is advantageousto carry out the oxygen plasma surface treatment, the oxide layerdeposition and the exterior layer deposition the same processing chamberwith no intermediate exposure of the golf ball to an uncontrolledambient. It is also possible to use a combination of processing chambersand to shuttle the golf balls from chamber to chamber under controlledenvironmental conditions.

In one preferred embodiment, when a hydrophobic exterior surface coatingwas applied to the golf balls, an oxygen plasma treatment, oxide layercreation and SAM layer application were typically carried out in asingle vacuum processing chamber. The pressure in the vacuum processingchamber is typically in the range of about 0.5 torr during the oxygenplasma treatment, in the range of about 6 Torr to 7 Torr duringformation of the oxide layer, and in the range of about 2 Torr to 6 Torrduring deposition of a SAM layer. The process chamber baseline pressure,prior to initiation of a treatment or deposition of a coating, is in therange of about 20 mTorr. During deposition of the exterior coatinglayer, which forms the exterior surface of the golf ball, controllingthe total pressure in the vacuum processing chamber, the number and kindof vaporous components charged to the process chamber, the partialpressure of each vaporous component, the substrate temperature, thetemperature of the process chamber walls, and the time over whichparticular conditions are maintained, enables control of the chemicalreactivity and properties of the exterior surface of the golf ball. Bycontrolling the process parameters, both density of film coverage overthe substrate surface and structural composition over the substratesurface are more accurately controlled. Very smooth films, whichtypically range from about 0.1 nm to less than about 5 nm, and even moretypically from about 1 nm to about 3 nm in surface RMS roughness may beapplied. These smooth oxide bonding films can be tailored in thickness,roughness, hydrophobicity/hydrophilicity, and density, which makes themable to bond to whatever silane-based functional organic coatings willprovide the desired behavior on the golf ball surface. For oxide filmsused to provide a bonding layer, the thickness of the oxide filmtypically ranges from about 50 Å to about 500 Å.

Oxide films deposited according to the present method can be used asbonding layers for subsequently deposited chlorosilane-based coatingsystems where one end of the organic molecule presents chlorosilane, andthe other end of the organic molecule presents a fluorine moiety. Afterattachment of the chlorosilane end of the organic molecule to thesubstrate, the fluorine moiety at the other end of the organic moleculeprovides a hydrophobic coating surface. Further, the degree ofhydrophobicity and the uniformity of the hydrophobic surface at a givenlocation across the coated surface may be controlled using theoxide-based layer which is applied over the substrate surface prior toapplication of the chlorosilane-comprising organic molecule. Bycontrolling the oxide-based layer application, the organic-based layeris controlled indirectly. For example, using the process variablespreviously described, we are able to control the concentration of OHreactive species on the substrate surface. This, in turn, controls thedensity of reaction sites needed for subsequent deposition of asilane-based polymeric coating. Control of the substrate surface activesite density enables uniform growth and application of high densityself-aligned monolayer coatings (SAMS), for example.

Organic-based functional hydrophobic layer precursors other than thesilanes may be used as well. The stability of the coating on theexterior surface of the golf ball frequently depends on the thickness ofthe oxide-based bonding layer. In some instances, better structuralstability is provided by a multilayered structure of repeated layers ofoxide-based bonding layers interleaved with organic-based layers.

In instances where it is desired to create multilayered coatings, forexample and not by way of limitation, it is advisable to use oxygenplasma treatment prior to and between coating deposition steps. Thisoxygen plasma treatment activates dangling bonds on the substratesurface, which dangling bonds may be exposed to a controlled partialpressure of water vapor to create a new concentration of OH reactivesites on the substrate surface. The coating deposition process may thenbe repeated, using a silane to create an oxide bonding layer or asilane-functionalized organic molecule to create a hydrophobic layer onthe golf ball surface, by way of example, and not by way of limitation.

The hydrophobicity of a given substrate surface may be measured using awater droplet shape analysis method, for example. The range inhydrophobicity of the exterior surface of the golf ball is typicallycontrolled to provide a water wetted contact angle ranging from about100° to about 125°. FIG. 3 shows a series of water contact anglesmeasured for various coated surfaces. The higher the contact angle, thehigher the hydrophobicity of the coating surface. A golf ball surfacehaving a hydrophilic surface is typically controlled to provide a waterwetted contact angle ranging from about 5° to about 60°.

A computer driven process control system may be used to provide for aseries of additions of reactants to the process chamber in which thelayer or coating is being formed. This process control system typicallyalso controls other process variables, such as (for example and not byway of limitation), total process chamber pressure (typically less thanatmospheric pressure), substrate temperature, temperature of processchamber walls, temperature of the vapor delivery manifolds, processingtime for given process steps, and other process parameters if needed.

As a preface to the more detailed description provided below, it shouldbe noted that, as used in this specification and the appended claims,the singular forms “a”, “an”, and “the” include plural referents, unlessthe context clearly dictates otherwise.

As a basis for understanding the invention, it is important to discuss aprocessing apparatus which permits precise control over the addition ofcoating precursors and other vaporous components present within thereaction/processing chamber in which the coating is applied. Theapparatus described below is not the only apparatus in which the presentinvention may be practiced, it is merely an example of one apparatuswhich may be used. One skilled in the art will recognize equivalentelements in other forms which may be substituted and still provide anacceptable processing system.

I. An Apparatus for Vapor Deposition of Thin Coatings

FIG. 1 shows a cross-sectional schematic of an apparatus 100 for vapordeposition of thin coatings. The apparatus 100 includes a processchamber 102 in which thin (typically 20 Å to 500 Å thick) coatings arevapor deposited. A substrate 106 to be coated rests upon a temperaturecontrolled substrate holder 104, typically within a recess 107 in thesubstrate holder 104.

Depending on the chamber design, the substrate 106 may rest on thechamber bottom (not shown in this position in FIG. 1). Attached toprocess chamber 102 is a remote plasma source 110, connected via a valve108. Remote plasma source 110 may be used to provide a plasma which isused to clean and/or convert a substrate surface to a particularchemical state prior to application of a coating (which enables reactionof coating species and/or catalyst with the surface, thus improvingadhesion and/or formation of the coating); or may be used to providespecies helpful during formation of the coating (not shown) ormodifications of the coating after deposition. The plasma may begenerated using a microwave, DC, or inductive RF power source, orcombinations thereof. The process chamber 102 makes use of an exhaustport 112 for the removal of reaction byproducts and is opened forpumping/purging the chamber 102. A shut-off valve or a control valve 114is used to isolate the chamber or to control the amount of vacuumapplied to the exhaust port. The vacuum source is not shown in FIG. 1.

The apparatus 100 shown in FIG. 1 is illustrative of a vapor depositedcoating which employs two precursor materials and a catalyst. Oneskilled in the art will understand that one or more precursors and fromzero to multiple catalysts may be used during vapor deposition of acoating. A catalyst storage container 116 contains catalyst 154, whichmay be heated using heater 118 to provide a vapor, as necessary. It isunderstood that precursor and catalyst storage container walls, andtransfer lines into process chamber 102 will be heated as necessary tomaintain a precursor or catalyst in a vaporous state, minimizing oravoiding condensation. The same is true with respect to heating of theinterior surfaces of process chamber 102 and the surface of substrate106 to which the coating (not shown) is applied. A control valve 120 ispresent on transfer line 119 between catalyst storage container 116 andcatalyst vapor reservoir 122, where the catalyst vapor is permitted toaccumulate until a nominal, specified pressure is measured at pressureindicator 124. Control valve 120 is in a normally-closed position andreturns to that position once the specified pressure is reached incatalyst vapor reservoir 122. At the time the catalyst vapor in vaporreservoir 122 is to be released, valve 126 on transfer line 119 isopened to permit entrance of the catalyst present in vapor reservoir 122into process chamber 102 which is at a lower pressure. Control valves120 and 126 are controlled by a programmable process control system ofthe kind known in the art (which is not shown in FIG. 1).

A Precursor 1 storage container 128 contains coating reactant Precursor1, which may be heated using heater 130 to provide a vapor, asnecessary. As previously mentioned, Precursor 1 transfer line 129 andvapor reservoir 134 internal surfaces are heated as necessary tomaintain a Precursor 1 in a vaporous state, minimizing and preferablyavoiding condensation. A control valve 132 is present on transfer line129 between Precursor 1 storage container 128 and Precursor 1 vaporreservoir 134, where the Precursor 1 vapor is permitted to accumulateuntil a nominal, specified pressure is measured at pressure indicator136. Control valve 132 is in a normally closed position and returns tothat position once the specified pressure is reached in Precursor 1vapor reservoir 134. At the time the Precursor 1 vapor in vaporreservoir 134 is to be released, valve 138 on transfer line 129 isopened to permit entrance of the Precursor 1 vapor present in vaporreservoir 134 into process chamber 102, which is at a lower pressure.Control valves 132 and 138 are controlled by a programmable processcontrol system of the kind known in the art (which is not shown in FIG.1).

A Precursor 2 storage container 140 contains coating reactant Precursor2, which may be heated using heater 142 to provide a vapor, asnecessary. As previously mentioned, Precursor 2 transfer line 141 andvapor reservoir 146 internal surfaces are heated as necessary tomaintain Precursor 2 in a vaporous state, minimizing, and preferablyavoiding condensation. A control valve 144 is present on transfer line141 between Precursor 2 storage container 146 and Precursor 2 vaporreservoir 146, where the Precursor 2 vapor is permitted to accumulateuntil a nominal, specified pressure is measured at pressure indicator148. Control valve 141 is in a normally-closed position and returns tothat position once the specified pressure is reached in Precursor 2vapor reservoir 146. At the time the Precursor 2 vapor in vaporreservoir 146 is to be released, valve 150 on transfer line 141 isopened to permit entrance of the Precursor 2 vapor present in vaporreservoir 146 into process chamber 102, which is at a lower pressure.Control valves 144 and 150 are controlled by a programmable processcontrol system of the kind known in the art (which is not shown in FIG.1).

During formation of a coating (not shown), golf ball surfaces 105 aresupported by a substrate holder 106, which typically is a supportingstructure which contains a number of golf balls, with pins holding thegolfballs in a manner that essentially all of the surface of thegolfballs is exposed during processing. At least one incrementaladdition of vapor equal to the vapor reservoir 122 of the catalyst 154,and the vapor reservoir 134 of the Precursor 1, or the vapor reservoir146 of Precursor 2 may be added to process chamber 102. The total amountof vapor added is controlled by both the adjustable volume size of eachof the expansion chambers (typically 50 cc up to 1,000 cc) and thenumber of vapor injections (doses) into the reaction chamber. Further,the set pressure 124 for catalyst vapor reservoir 122, or the setpressure 136 for Precursor 1 vapor reservoir 134, or the set pressure148 for Precursor 2 vapor reservoir 146, may be adjusted to control theamount (partial vapor pressure) of the catalyst or reactant added to anyparticular step during the coating formation process. This ability tocontrol precise amounts of catalyst and vaporous precursors to be dosed(charged) to the process chamber 102 at a specified time provides notonly accurate dosing of reactants and catalysts, but repeatability inthe vapor charging sequence.

This apparatus provides a relatively inexpensive, yet accurate method ofadding vapor phase precursor reactants and catalyst to the coatingformation process, despite the fact that many of the precursors andcatalysts are typically relatively non-volatile materials. In the past,flow controllers were used to control the addition of various reactants;however, these flow controllers may not be able to handle some of theprecursors used for vapor deposition of coatings, due to the low vaporpressure and chemical nature of the precursor materials. The rate atwhich vapor is generated from some of the precursors is generally tooslow to function with a flow controller in a manner which providesavailability of material in a timely manner for the vapor depositionprocess.

The apparatus discussed above allows for accumulation of the specificquantity of vapor in the vapor reservoir which can be charged (dosed) tothe reaction. In the event it is desired to make several doses duringthe coating process, the apparatus can be programmed to do so, asdescribed above. Additionally, adding of the reactant vapors into thereaction chamber in controlled aliquots (as opposed to continuous flow)greatly reduces the amount of the reactants used and the cost of thecoating.

One skilled in the art of chemical processing of a number of substrates,such as golf balls, simultaneously will recognize that a processingsystem which permits heat and mass transfer uniformly over the entiresurface of substrate is important. A number of different designs ofsubstrate holders for golfballs are possible which will permit coatingof essentially all of the golf ball surface. In addition, it is possibleto rotate the golf ball and repeat the treatment or coating depositionstep prior to going on to the next step in the coating process to ensurethat the entire surface of the golf ball is coated. For example, theball may be rotated during progress of the plasma cleaning step, duringprocess of the oxide layer formation, and during deposition of thefunctional organic precursor material which forms a hydrophobic surfaceon the exterior of the golf ball.

II. Exemplary Embodiments of the Method of the Invention:

A method of the invention provides for vapor-phase deposition ofcoatings onto a golf ball surface, where a processing chamber of thekind, or similar to the processing chamber described above is employed.Each coating precursor is transferred in vaporous form to a precursorvapor reservoir in which the precursor vapor accumulates. A nominalamount of the precursor vapor, which is the amount required for acoating layer deposition is accumulated in the precursor vaporreservoir. The at least one coating precursor is charged from theprecursor vapor reservoir into the processing chamber in which thegolfballs are to be coated. In some instances at least one catalystvapor is added to the process chamber in addition to the at least oneprecursor vapor, where the relative quantities of catalyst and precursorvapors are based on the physical characteristics to be exhibited by thecoating. In some instances a diluent gas is added to the process chamberin addition to the at least one precursor vapor (and optional catalystvapor). The diluent gas is chemically inert and is used to increase atotal desired processing pressure, while the partial pressure amounts ofcoating precursors and optionally catalyst components are varied.

The example embodiments described below are with reference to formationof a bonding oxide layer with an overlying silane-based polymeric layerwhich presents a hydrophobic functional group on the outer surface ofthe golf ball. However, it is readily apparent to one of skill in theart that the concepts involved can be applied to additional coatingcompositions and combinations which have different functionalities, toprovide golf balls having additional functional characteristics.

Due to the need to control the functionality of the coating atdimensions as small as nanometers, the surface preparation of thegolfball substrate, typically a cover layer of the golf ball of the kindknown generally in the art, prior to application of the coating is veryimportant. As an initial, optional step, the golf ball may be wiped,dipped, or sprayed (for example) with a degreasing solvent which willnot attack the surface of the golf ball cover. As previously described,we used isopropyl alcohol for degreasing of the ball surface.Subsequently, the golf ball surface was treated to remove contaminantsby exposure to a uniform, non-physically-bombarding plasma which istypically created from a plasma source gas containing oxygen. The plasmamay be a remotely generated plasma which is fed into a processingchamber in which a substrate to be coated resides. Depending on thecoating to be applied directly over the golf ball surface, the plasmatreatment of the golf ball surface may be carried out in the chamber inwhich the coating is to be applied. This has the advantage that the golfball surface is easily maintained in a controlled environment betweenthe time that the surface is treated in preparation for coating, and thetime at which the coating is applied. Alternatively, it is possible touse a large system which includes several processing chambers and acentralized transfer chamber which allows transfer of golf balls fromone chamber to another via a robot handling device, where thecentralized handling chamber as well as the individual processingchambers are each under a controlled environment. A single chamber golfball coating device is advantageous in size and cost. Replaceable linerscan be used inside the chamber and replaced periodically, as a means ofpreventing oxide and organic polymeric build-up on the process chamberwalls.

Depending on the polymeric composition on the golf ball cover, in someinstances it is necessary not only to remove contaminants from thesurface of the golf ball, but also to generate —OH functional groups onthe surface of the golf ball cover material (in instances where such —OHfunctional groups are not already present).

When a silicon oxide layer is applied to the golfball surface, toprovide a bonding layer, the oxide layer may be created using thewell-known catalytic hydrolysis of a chlorosilane, such as atetrachlorosilane, in the manner previously described. A subsequentattachment of an organo-chlorosilane, which may or may not include afunctional moiety, may be made to impart a particular function to thefinished coating. By way of example and not by way of limitation, thehydrophobicity or hydrophilicity of the coating surface may be alteredby the functional moiety present on a surface of an organo-chlorosilanewhich becomes the exterior surface of the coating.

The oxide layer, which may be silicon oxide or another oxide, may beformed using the method of the present invention by vapor phasehydrolysis of the chlorosilane, with subsequent attachment of thehydrolyzed silane to the substrate surface. Alternatively, thehydrolysis reaction may take place directly on the surface of the golfball, where moisture has been made available on the golf ball surface toallow simultaneous hydrolyzation and attachment of the chlorosilane tothe golf ball surface. The hydrolysis in the vapor phase usingrelatively wide range of partial pressure of the silicon tetrachlorideprecursor in combination with a partial pressure in the range of 10 Torror greater of water vapor will generally result in rougher surfaces onthe order of 5 nm RMS or greater, where the thickness of the film formedwill typically be in the range of about 20 nm or greater. Thinner filmsof the kind enabled by one of the embodiments of applicants' inventiontypically exhibit a 1-5 nm RMS finish and are grown by carefullybalancing the vapor and surface hydrolysis reaction components. Forexample, and not by way of limitation, for a thin film of an oxide-basedlayer, prepared on a silicon substrate, where the oxide-based layerexhibits a thickness ranging from about 2 nm to about 15 nm, typicallythe oxide-based layer exhibits a 1-5 nm RMS finish. We have obtainedsuch films in an apparatus of the kind previously described, where thepartial pressure of the silicon tetrachloride is in the range of about0.5 to 4.0 Torr, the partial pressure of the water vapor is in the rangeof about 2 to about 8 Torr, where the total process chamber pressureranges from about 3 Torr to about 10 Torr, where the golfballtemperature ranges from about 20° C. to about 60° C., where the processchamber walls are at a temperature ranging from about 30° C. to about60° C., and where the time period over which the golf ball is exposed tothe combination of silicon tetrachloride and water vapor ranges fromabout 2 minutes to about 12 minutes. This deposition process will bedescribed in more detail subsequently herein, with reference to FIGS. 6Athrough 6C.

A multilayered coating process may include plasma treatment of thesurface of one deposited layer prior to application of an overlyinglayer. Typically, the plasma used for such treatment is a low densityplasma. This plasma may be a remotely generated plasma. The mostimportant feature of the treatment plasma is that it is a “soft” plasmawhich affects the exposed surface enough to activate the surface of thelayer being treated, but not enough to etch through the layer. Theapparatus used to carry out the method provides for the addition of aprecise amount of each of the reactants to be consumed in a singlereaction step of the coating formation process. The apparatus mayprovide for precise addition of different combinations of reactantsduring each individual step when there are a series of differentindividual steps in the coating formation process. Some of theindividual steps may be repetitive.

One example of the application of the method described here isdeposition of a multilayered coating including at least one oxide-basedlayer. The thickness of the oxide-based layer depends on the end-useapplication for the multilayered coating. The oxide-based layer (or aseries of oxide-based layers alternated with organic-based layers) maybe used to increase the overall thickness of the multilayered coating(which typically derives the majority of its thickness from theoxide-based layer), and depending on the mechanical properties to beobtained, the oxide-based layer content of the multilayered coating maybe increased when more coating rigidity and abrasion resistance isrequired.

The oxide-based layer is frequently used to provide a bonding surfacefor subsequently deposited various molecular organic-based coatinglayers. When the surface of the oxide-based layer is one containing —OHfunctional groups, the organic-based coating layer typically includes,for example and not by way of limitation, a silane-based functionalitywhich permits covalent bonding of the organic-based coating layer to —OHfunctional groups present on the surface of the oxide-based layer. Whenthe surface of the oxide-based layer is one capped with halogenfunctional groups, such as chlorine, by way of example and not by way oflimitation, the organic-based coating layer includes, for example, an—OH functional group, which permits covalent bonding of theorganic-based coating layer to the oxide-based layer functional halogengroup.

By controlling the precise thickness, chemical, and structuralcomposition of an oxide-based layer on a golf ball, for example, we areable to direct the coverage and the functionality of a coating appliedover the bonding oxide layer. The coverage and functionality of thecoating can be controlled over the entire golf ball surface on a nmscale. Specific, different thicknesses of an oxide-based golf ballbonding layer are required on different golf balls covering layers. Somegolf ball cover layers require an alternating series ofoxide-based/organic-based layers to provide surface stability for acoating structure.

With respect to golf ball surface properties, such as hydrophobicity orhydrophilicity, for example, a silicon surface becomes hydrophilic, toprovide a 5 degree water contact angle (or less), after plasma treatmentwhen there is some moisture present. Not much moisture is required, forexample, typically the amount of moisture present after pumping achamber from ambient air down to about 15 mTorr to 20 mTorr issufficient moisture. Glass and polystyrene materials become hydrophilic,to a 5 degree water contact angle, after the application of about 80 Åor more of an oxide-based layer. An acrylic surface requires about 150 Åor more of an oxide-based layer to provide a 5 degree water contactangle.

There is also a required thickness of oxide-based layer to provide agood bonding surface for reaction with a subsequently appliedorganic-based layer. By a good bonding surface, it is meant a surfacewhich provides full, uniform surface coverage of the organic-basedlayer. By way of example, about 80 Å or more of a oxide-based bondinglayer over a silicon substrate provides a uniform hydrophobic contactangle, about 112 degrees, upon application of a SAM organic-based layerdeposited from an FDTS (perfluorodecyltrichlorosilanes) precursor. About150 Å or more of oxide-based substrate bonding layer is required over aglass substrate or a polystyrene substrate to obtain a uniform coatinghaving a similar contact angle. About 400 Å or more of oxide-basedsubstrate bonding layer is required over an acrylic substrate to obtaina uniform coating having a similar contact angle.

The organic-based layer precursor, in addition to containing afunctional group capable of reacting with the oxide-based layer toprovide a covalent bond, may also contain a functional group at alocation which will form the exterior surface of the attachedorganic-based layer. This functional group may subsequently be reactedwith other organic-based precursors, or may be the final layer of thecoating and be used to provide surface properties of the coating, suchas to render the surface hydrophobic or hydrophilic, by way of exampleand not by way of limitation. The functionality of an attachedorganic-based layer may be affected by the chemical composition of theprevious organic-based layer (or the chemical composition of the initialsubstrate) if the thickness of the oxide layer separating the attachedorganic-based layer from the previous organic-based layer (or othersubstrate) is inadequate. The required oxide-based layer thickness is afunction of the chemical composition of the substrate surface underlyingthe oxide-based layer, as illustrated above. In some instances, toprovide structural stability for the surface layer of the coating, it isnecessary to apply several alternating layers of an oxide-based layerand an organic-based layer.

With reference to chlorosilane-based coating systems of the kinddescribed in the Background Art section of this application, where oneend of the organic molecule presents chlorosilane, and the other end ofthe organic molecule presents a fluorine moiety, after attachment of thechlorosilane end of the organic molecule to the substrate, the fluorinemoiety at the other end of the organic molecule provides a hydrophobiccoating surface. Further, the degree of hydrophobicity and theuniformity of the hydrophobic surface at a given location across thecoated surface may be controlled using the oxide-based layer which isapplied over the substrate surface prior to application of thechlorosilane-comprising organic molecule. By controlling the oxide-basedlayer application, the organic-based layer is controlled indirectly. Forexample, using the process variables previously described, we are ableto control the concentration of OH reactive species on the substratesurface. This, in turn, controls the density of reaction sites neededfor subsequent deposition of a silane-based polymeric coating. Controlof the substrate surface active site density enables uniform growth andapplication of high density self-aligned monolayer coatings (SAMS), forexample.

We have discovered that it is possible to convert a hydrophilic-likesubstrate surface to a hydrophobic surface by application of anoxide-based layer of the minimal thickness described above with respectto a given substrate, followed by application of an organic-based layerover the oxide-based layer, where the organic-based layer provideshydrophobic surface functional groups on the end of the organic moleculewhich does not react with the oxide-based layer. However, when theinitial substrate surface is a hydrophobic surface and it is desired toconvert this surface to a hydrophilic surface, it is necessary to use astructure which comprises more than one oxide-based layer to obtainstability of the applied hydrophilic surface in water. It is not alwaysjust the thickness of the oxide-based layer or the thickness of theorganic-based layer which is controlling. The structural stabilityprovided by a multilayered structure of repeated layers of oxide-basedmaterial interleaved with organic-based layers provides excellentresults.

After deposition of a first organic-based layer, and prior to thedeposition of a subsequent layer in a multilayered coating, it isadvisable to use an in-situ oxygen plasma treatment. This treatmentactivates reaction sites of the first organic-based layer and may beused as part of a process for generating an oxide-based layer or simplyto activate dangling bonds on the substrate surface. The activateddangling bonds may be exploited to provide reactive sites on thesubstrate surface. For example, an oxygen plasma treatment incombination with a controlled partial pressure of water vapor may beused to create a new concentration of OH reactive species on an exposedsurface. The activated surface is then used to provide covalent bondingwith the next layer of material applied. A deposition process may thenbe repeated, increasing the total coating thickness, and eventuallyproviding a surface layer having the desired surface properties. In someinstances, where the substrate surface includes metal atoms, treatmentwith the oxygen plasma and moisture provides a metal oxide-based layercontaining —OH functional groups. This oxide-based layer is useful forincreasing the overall thickness of the multilayered coating and forimproving mechanical strength and rigidity of the multilayered coating.

EXAMPLE ONE

Deposition of a Silicon Oxide Layer Having a Controlled Number of OHReactive Sites Available on the Oxide Layer Surface

FIG. 2 shows a schematic 200 of the mechanism of bonding oxide layerformation. In particular, a substrate 202, plasma-cleaned golf balllayer surface, for example, may have some OH groups 204 present on thesurface 203. A chlorosilane 208, such as the tetrachlorosilane shown,and water 206 are reacted with the OH groups 204, either simultaneouslyor in sequence, to produce the oxide layer 205 shown on surface 203 ofsubstrate 202 and byproduct HCl 210. In addition to chlorosilaneprecursors, chlorosiloxanes, fluorosilanes, and fluorosiloxanes may beused to provide the oxide bonding layer.

Subsequently, the surface of the oxide layer 205 can be further reactedwith water 216 to replace C1 atoms on the upper surface of oxide layer205 with OH groups 217, to produce the hydroxylated layer 215 shown onsurface 203 of substrate 202 and byproduct HCl 220. By controlling theamount of water used in both reactions, the frequency of OH reactivesites available on the oxide surface is controlled. The process may berepeated any number of times to produce an oxide bonding layer of thedesired thickness.

EXAMPLE TWO

To evaluate process parameters useful in preparation of a silicon oxidebonding layer, silicon oxide layers were applied over a glass substrate.The glass substrate was treated with an oxygen plasma in the presence ofresidual moisture which was present in the process chamber (after pumpdown of the chamber to about 20 mTorr) to provide a clean surface (freefrom organic contaminants) and to provide the initial OH groups on theglass surface.

Various process conditions for the subsequent reaction of the OH groupson the glass surface with vaporous tetrachlorosilane and water areprovided below in Table I, along with data related to the thickness androughness of the oxide coating obtained and the contact angle(indicating hydrophobicity/hydrophilicity) obtained under the respectiveprocess conditions. A lower contact angle indicates increasedhydrophilicity and an increase in the number of available OH groups onthe silicon oxide surface. TABLE I Deposition of a Silicon Oxide Layerof Varying Hydrophilicity Partial Partial Pressure Pressure SiO₂ OrderSiCl₄ H₂O Reaction Coating Coating Contact Run of Vapor Vapor TimeThickness Roughness Angle*** No. Dosing (Torr) (Torr) (min.) (nm) (RMS,nm)* (°) 1 First² 0.8 4.0 10 3 1 <5 SiCl₄ 2 First¹ 4.0 10.0 10 35 5 <5H₂O 3 First² 4.0 10.0 10 30 4 <5 SiCl₄ Partial Partial FOTS PressurePressure Surface Order FOTS H₂O Reaction Coating Coating Contact ofVapor Vapor Time Thickness Roughness Angle*** Dosing (Torr) (Torr)(min.) (nm)** (RMS, nm)* (°) 1 First³ 0.2 0.8 15 4 1 108 FOTS 2 First³0.2 0.8 15 36 5 109 FOTS 3 First³ 0.2 0.8 15 31 4 109 FOTS*Coating roughness is the RMS roughness measured by AFM (atomic forcemicroscopy).**The FOTS coating layer was a monolayer which added ≈1 nm in thickness.***Contact angles were measured with 18 MΩ D.I. water.¹The H₂O was added to the process chamber 10 seconds before the SiCl₄was added to the process chamber.²The SiCl₄ was added to the process chamber 10 seconds before the H₂Owas added to the process chamber.³The FOTS was added to the process chamber 5 seconds before the H₂O wasadded to the process chamber.⁴The substrate temperature and the chamber wall temperature were each35° C. for both application of the SiO₂ bonding/bonding layer and forapplication of the FOTS organosilane overlying monolayer (SAM) layer.

We learned that very different film thicknesses and film surfaceroughness characteristics can be obtained as a function of the partialpressures of the precursors, despite the maintenance of the same timeperiod of exposure to the precursors. Table II below illustrates thisunexpected result. TABLE II Response Surface Design* Silicon Oxide LayerDeposition Partial Partial Substrate Coating Pressure Pressure andSurface Total SiCl₄ H₂O Chamber Reaction Coating Roughness Run PressureVapor Vapor Wall Temp. Time Thickness RMS No. (Torr) (Torr) (Torr) (°C.) (min.) (nm) (nm) 1 9.4 2.4 7 35 7 8.8 NA 2 4.8 0.8 4 35 7 2.4 1.29 36.4 2.4 4 35 4 3.8 1.39 4 14.0 4.0 10 35 7 21.9 NA 5 7.8 0.8 7 35 4 4.02.26 6 11.0 4.0 7 35 10 9.7 NA 7 11.0 4.0 7 35 4 10.5 NA 8 12.4 2.4 1035 4 14.0 NA 9 6.4 2.4 4 35 10 4.4 1.39 10 9.4 2.4 7 35 7 8.7 NA 11 12.42.4 10 35 10 18.7 NA 12 9.4 2.4 7 35 7 9.5 NA 13 8.0 4.8 4 35 7 6.2 2.1614 10.8 0.8 10 35 7 6.9 NA 15 7.8 0.8 7 35 10 4.4 2.24*(Box-Behnken) 3 Factors, 3 Center PointsNA = Not Available, Not Measured

In addition to the tetrachlorosilane described above as a precursor foroxide formation, other chlorosilane precursors such a trichlorosilanes,dichlorosilanes work well as a precursor for oxide formation. Examplesof specific advantageous precursors include hexachlorodisilane (Si₂Cl₆)and hexachlorodisiloxane (Si₂Cl₆O). As previously mentioned, in additionto chlorosilanes, chlorosiloxanes, fluorosilanes, and fluorosiloxanesmay also be used as precursors.

Similarly, the vapor deposited silicon oxide coating from the SiCl₄ andH₂O precursors was applied over glass, polycarbonate, acrylic,polyethylene and other plastic materials using the same processconditions as those described above. Prior to application of the siliconoxide coating, the surface to be coated was treated with an oxygenplasma.

EXAMPLE THREE

In the preferred embodiment discussed in detail below, the silicon oxidebonding layer was applied over golf ball having a polymeric cover layerof ionomer, which exhibited a contact angle coming out of the box whichranged between about 80° and about 90°. The golf ball was wiped withisopropyl alcohol to remove any grease or oils present on the golf ballsurface. The golf ball surface was then treated with an oxygen plasma inthe presence of residual moisture which was present in the processchamber (after pump down of the chamber to about 20 mTorr) to provide aclean surface (free from organic contaminants) and to provide theinitial OH groups on the golf ball surface. In a process chamber of thekind described above, the flow rate of oxygen was about 400 sccm, andthe RF power applied to create the plasma was about 200 W, with theexposure time of the golf ball being about 5 minutes at 35° C.

A silicon oxide coating of the kind described above was applied over thegolf ball surfaces by treatment with a combination of silicontetrachloride and water vapor in the manner described above. Thisproduced a hydrophilic surface on the golf balls. In one embodiment theamount of silicon tetrachloride (SiCl₄) charged to the reactor was 1each 300 cc volumetric charge at 18 Torr, which was used in combinationwith 4 each 300 cc volumetric charges at 18 Torr of water (H₂O). Thepressure in the process chamber with all reagents added was about 7Torr, the temperature in the process chamber was about 35° C., and thedeposition time period (reaction time) was about 10 minutes. Thisproduced an oxide coating having a thickness of about 120 Å to about 150Å. This oxide thickness is acceptable for use as a bonding oxide layer.

When the oxide layer is to be used as a single layer to provide ahydrophilic surface on the golf ball, a thicker coating is preferred. Acoating having a thickness ranging from about 200 Å to about 2,000 Å maybe used. The thicker coating may be generated using the processdescribed above, where the deposition step is repeated a number oftimes. The length of the repeated step commonly ranges from about 2minutes to about 10 minutes, depending on the overall thickness of theoxide layer which is to be obtained.

When the oxide layer is to act as a bonding layer, subsequent todeposition of the oxide layer, a functionalized organic layer is appliedover the surface of the oxide layer to create a specialized hydrophilicor a hydrophobic surface.

When the exterior surface on the golf ball is to be a specializedhydrophilic surface, a functionalized organic material such as a silanefunctionalized PEO or PEG layer may be deposited over the oxide bondinglayer. The functionalized silane precursor vapor containing PEO/PEGgroups may be reacted with the hydrophilic silicon oxide layer to form alayer selected from the group consisting of a monolayer, a self-alignedmono-layer, and a polymerized cross-linked layer. Although just onelayer of PEO/PEG may be applied, when it is desired to increase thethickness of the PEO/PEG layer, the deposition step may be repeated anumber of times. For example, to apply an mPEG layer, mPEG(methoxy(polyethyleneoxy) propyltrimethoxysilane, Gelest P/N SIM 6492.7,MW=450−620 was used, or to apply a PEG layer, (polyethyleneoxy)propyltrichlorosilane, Gelest P/N SIM 6492.66, MW=450−620) was chargedto the process chamber from a vapor reservoir of 300 cc, where the mPEGor PEG vapor pressure in the vapor reservoir was about 0.5 Torr.(Combinations of mPEG with PEG may also be used.) Four chamber volumesof mPEG or PEG were charged, creating a partial pressure of about 250mTorr in the coating process chamber. The substrate was exposed to mPEGvapor or to the PEG vapor each time for a time period of 15 minutes. Thesubstrate temperature and the temperature of the process chamber wallswas about 350° C. The MPEG coating or PEG coating thickness obtained wasabout 20 Å.

When the exterior surface on the golf ball is to be a hydrophobicsurface, a self aligned monolayer (SAM) coating formed from an organicprecursor, for example and not by way of limitation fromfluoro-tetrahydrooctyldimethylchlorosilane (FOTS), or fromperfluorodecyltrichlorosilane (FDTS) may be applied over an oxidebonding layer. A FDTS hydrophobic exterior surface layer may be appliedusing 4 each 300 cc volumes at 0.5 Torr of FDTS and 1 each 300 cc volumeat 18 Torr of H₂O. The overall pressure in the process chamber afteraddition of all reactants was about 5 Torr, the temperature in theprocess chamber was about 35° C., and the deposition time period(reaction time) was about 15 minutes. This produced a FDTS coatingthickness of about 15 Å.

Functional properties designed to meet a particular functionality forthe golf ball can be tailored by either sequentially adding anorgano-silane precursor to the oxide coating precursors or by using anorgano-silane precursor(s) for formation of the last, top layer coating.Organo-silane precursor materials may include functional groups suchthat the silane precursor includes an alkyl group, an alkoxyl group, analkyl substituted group containing fluorine, an alkoxyl substitutedgroup containing fluorine, a vinyl group, an ethynyl group, or asubstituted group containing a silicon atom or an oxygen atom, by way ofexample and not by way of limitation. In particular, organic-containingprecursor materials such as (and not by way of limitation) silanes,chlorosilanes, fluorosilanes, methoxy silanes, alkyl silanes, aminosilanes, epoxy silanes, glycoxy silanes, and acrylosilanes are useful ingeneral.

Some of the particular precursors used to produce coatings are, by wayof example and not by way of limitation, perfluorodecyltrichlorosilanes(FDTS), undecenyltrichlorosilanes (UTS), vinyl-trichlorosilanes (VTS),decyltrichlorosilanes (DTS), octadecyltrichlorosilanes (OTS),dimethyldichlorosilanes (DDMS), dodecenyltricholrosilanes (DDTS),fluoro-tetrahydrooctyldimethylchlorosilanes (FOTS),perfluorooctyldimethylchlorosilanes, aminopropylmethoxysilanes (APTMS),fluoropropylmethyldichlorosilanes, andperfluorodecyldimethylchlorosilanes. The OTS, DTS, UTS, VTS, DDTS, FOTS,and FDTS are all trichlorosilane precursors. The other end of theprecursor chain is a saturated hydrocarbon with respect to OTS, DTS, andUTS; contains a vinyl functional group, with respect to VTS and DDTS;and contains fluorine atoms with respect to FDTS (which also hasfluorine atoms along the majority of the chain length). Other usefulprecursors include 3-aminopropyltrimethoxysilane (APTMS), which providesamino functionality, and 3-glycidoxypropyltrimethoxysilane (GPTMS). Oneskilled in the art of organic chemistry can see that the vapor depositedcoatings from these precursors can be tailored to provide particularfunctional characteristics for a coated surface. The use of precursorswhich provide a fluorine-containing surface as the exterior surface ofthe golf ball provide excellent hydrophobic properties. These precursorsare favored in the present golf ball applications.

Most of the silane-based precursors, such as commonly used di- andtri-chlorosilanes, for example and not by way of limitation, tend tocreate agglomerates on the surface of the substrate during the coatingformation. These agglomerates can cause structure malfunctioning orstiction. Such agglomerations are produced by partial hydrolysis andpolycondensation of the polychlorosilanes. This agglomeration can beprevented by precise metering of moisture in the process ambient whichis a source of the hydrolysis, and by carefully controlled metering ofthe availability of the chlorosilane precursors to the coating formationprocess. The carefully metered amounts of material and carefultemperature control of the substrate and the process chamber walls canprovide the partial vapor pressure and condensation surfaces necessaryto control formation of the coating on the surface of the substraterather than promoting undesired reactions in the vapor phase or on theprocess chamber walls.

EXAMPLE FOUR

When the oxide-forming silane and the organo-silane which includes thefunctional moiety are deposited simultaneously (co-deposited), thereaction may be so rapid that the sequence of precursor addition to theprocess chamber becomes critical. For example, in a co-depositionprocess of SiCl₄/FOTS/H₂O, if the FOTS is introduced first, it depositson the glass substrate surface very rapidly in the form of islands,preventing the deposition of a homogeneous composite film. Examples ofthis are provided in Table III, below.

When the oxide-forming silane is applied to the substrate surface first,to form the oxide layer with a controlled density of potential OHreactive sites available on the surface, the subsequent reaction of theoxide surface with a FOTS precursor provides a uniform film without thepresence of agglomerated islands of polymeric material, examples of thisare provided in Table III below. TABLE III Deposition of a Coating Upona Silicon Substrate* Using Silicon tetrachloride and FOTS PrecursorsSubstrate Partial Partial Partial and Total Pressure Pressure PressureChamber Pres- SiCl₄ FOTS H₂O Wall Run sure Vapor Vapor Vapor Temp. No.(Torr) (Torr) (Torr) (Torr) (° C.) 1 FOTS + H₂O 1 — 0.2 0.8 35 2 H₂O +SiCl₄ 141 4 — 100.8 35 followed by — 0.20 FOTS + H₂O 3 FOTS + 14.2 4 0.210 35 SiCl₄ + H₂O 4 SiCl₄ + H₂O 14 4 — 10 35 5 SiCl₄ + H₂O 5.8 0.8 — 535 6 SiCl₄ + H₂O 14 4 — 10 35 repeated twice Coating Reaction CoatingRoughness Contact Time Thickness (nm)** Angle*** (min.) (nm) RMS (°) 115 0.7 0.1 110 2 10 + 15 35.5 4.8 110 3 15 1.5 0.8 110 4 10 30 0.9 <5 510 4 0.8 <5 6 10 + 10 55 1 <5*The silicon substrates used to prepare experimental samples describedherein exhibited an initial surface RMS roughness in the range of about0.1 nm, as measured by Atomic Force Microscope (AFM).**Coating roughness is the RMS roughness measured by AFM.***Contact angles were measured with 18 MΩ D.I. water.

An example process description for Run No. 2 was as follows.

Step 1. Pump down the reactor and purge out the residual air andmoisture to a final baseline pressure of about 30 mTorr or less.

Step 2. Perform O₂ plasma clean of the substrate surface to eliminateresidual surface contamination and to oxygenate/hydroxylate thesubstrate. The cleaning plasma is an oxygen-containing plasma. Typicallythe plasma source is a remote plasma source, which may employ aninductive power source. However, other plasma generation apparatus maybe used. In any case, the plasma treatment of the substrate is typicallycarried out in the coating application process chamber. The plasmadensity/efficiency should be adequate to provide a substrate surfaceafter plasma treatment which exhibits a contact angle of about 10° orless when measured with 18 MΩ D.I. water. The coating chamber pressureduring plasma treatment of the substrate surface in the coating chamberwas 0.5 Torr, and the duration of substrate exposure to the plasma was 5minutes.

Step 3. Inject SiCl₄ and within 10 seconds inject water vapor at aspecific partial pressure ratio to the SiCl₄, to form a silicon oxidebase layer on the substrate. For example, for the glass substratediscussed in Table III, 1 volume (300 cc at 100 Torr) of SiCl₄ to apartial pressure of 4 Torr was injected, then, within 10 seconds 10volumes (300 cc at 17 Torr each) of water vapor were injected to producea partial pressure of 10 Torr in the process chamber, so that thevolumetric pressure ratio of water vapor to silicon tetrachloride isabout 2.5. The substrate was exposed to this gas mixture for 1 min to 15minutes, typically for about 10 minutes. The substrate temperature inthe examples described above was in the range of about 35° C. Substratetemperature may be in the range from about 20° C. to about 80° C. Theprocess chamber surfaces were also in the range of about 35° C.

Step 4. Evacuate the reactor to <30 mTorr to remove the reactants.

Step 5. Introduce the chlorosilane precursor and water vapor to form ahydrophobic coating. In the example in Table III, FOTS vapor wasinjected first to the charging reservoir, and then into the coatingprocess chamber, to provide a FOTS partial pressure of 200 mTorr in theprocess chamber, then, within 10 seconds, H₂O vapor (300 cc at 12 Torr)was injected to provide a partial pressure of about 800 mTorr, so thatthe total reaction pressure in the chamber was 1 Torr. The substrate wasexposed to this mixture for 5 to 30 minutes, typically 15 minutes, wherethe substrate temperature was about 35° C. Again, the process chambersurface was also at about 35° C.

An example process description for Run No. 3 was as follows.

Step 1. Pump down the reactor and purge out the residual air andmoisture to a final baseline pressure of about 30 mTorr or less.

Step 2. Perform remote O₂ plasma clean to eliminate residual surfacecontamination and to oxygenate/hydroxylate the glass substrate. Processconditions for the plasma treatment were the same as described abovewith reference to Run No. 2.

Step 3. Inject FOTS into the coating process chamber to produce a 200mTorr partial pressure in the process chamber. Then, inject 1 volume(300 cc at 100 Torr) of SiCl₄ from a vapor reservoir into the coatingprocess chamber, to a partial pressure of 4 Torr in the process chamber.Then, within 10 seconds, inject ten volumes (300 cc at 17 Torr each) ofwater vapor from a vapor reservoir into the coating process chamber, toa partial pressure of 10 Torr in the coating process chamber. Totalpressure in the process chamber is then about 14 Torr. The substratetemperature was in the range of about 35° C. for the specific examplesdescribed, but could range from about 15° C. to about 80° C. Thesubstrate was exposed to this three gas mixture for about 1-15 minutes,typically about 10 minutes.

Step 4. Evacuate the process chamber to a pressure of about 30 mTorr toremove excess reactants.

EXAMPLE FIVE

FIG. 5 illustrates contact angles for a series of surfaces exposed towater, where the surfaces exhibited different hydrophobicity, with anincrease in contact angle representing increased hydrophobicity. Thisdata is provided as an illustration to make the contact angle datapresented in tables herein more meaningful.

EXAMPLE SIX

FIG. 4A shows a three dimensional schematic 400 of film thickness of asilicon oxide bonding layer coating deposited on a silicon surface as afunction of the partial pressure of silicon tetrachloride and thepartial pressure of water vapor present in the process chamber duringdeposition of the silicon oxide coating, where the temperature of thesubstrate and of the coating process chamber walls was about 35° C., andthe time period the silicon substrate was exposed to the coatingprecursors was four minutes after completion of addition of allprecursor materials. The precursor SiCl₄ vapor was added to the processchamber first, with the precursor H₂O vapor added within 10 secondsthereafter. The partial pressure of the H₂O in the coating processchamber is shown on axis 402, with the partial pressure of the SiCl₄shown on axis 404. The film thickness is shown on axis 406 in Angstroms.The film deposition time after addition of the precursors was 4 minutes.The thinner coatings exhibited a smoother surface, with the RMSroughness of a coating at point 408 on Graph 400 being in the range of 1nm (10 Å). The thicker coatings exhibited a rougher surface, which wasstill smooth relative to coatings generally known in the art. At point410 on Graph 400, the RMS roughness of the coating was in the range of 4nm (40 Å). FIG. 5A shows a three dimensional schematic 500 of the filmroughness in RMS, nm which corresponds with the coated substrate forwhich the coating thickness is illustrated in FIG. 4A. The partialpressure of the H₂O in the coating process chamber is shown on axis 502,with the partial pressure of the SiCl₄ shown on axis 504. The filmroughness in RMS, nm is shown on axis 506. The film deposition timeafter addition of all of the precursors was 7 minutes. As previouslymentioned, the thinner coatings exhibited a smoother surface, with theRMS roughness of a coating at point 508 being in the range of 1 nm (10Å) and the roughness at point 510 being in the range of 4 nm (40 Å).

FIG. 4B shows a three dimensional schematic 420 of film thickness of thesilicon oxide bonding layer illustrated in FIG. 4A as a function of thewater vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials. The time period of exposure of the substrate isshown on axis 422 in minutes, with the H₂O partial pressure shown onaxis 424 in Torr, and the oxide coating thickness shown on axis 426 inAngstroms. The partial pressure of SiCl₄ in the silicon oxide coatingdeposition chamber was 0.8 Torr.

FIG. 4C shows a three dimensional schematic 440 of film thickness of thesilicon oxide bonding layer illustrated in FIG. 4A as a function of thesilicon tetrachloride partial pressure and the time period the substratewas exposed to the coating precursors after completion of addition ofall precursor materials. The time period of exposure is shown on axis442 in minutes, with the SiCl₄ partial pressure shown on axis 446 inTorr, and the oxide thickness shown on axis 446 in Angstroms. The H₂Opartial pressure in the silicon oxide coating deposition chamber was 4Torr.

A comparison of FIGS. 4A-4C makes it clear that it is the partialpressure of the H₂O which must be more carefully controlled in order toensure that the desired coating thickness is obtained.

FIG. 5B shows a three dimensional schematic 520 of film roughness of thesilicon oxide bonding layer illustrated in FIG. 4B as a function of thewater vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials. The time period of exposure of the substrate isshown on axis 522 in minutes, with the H₂O partial pressure shown onaxis 524 in Torr, and the surface roughness of the silicon oxide layershown on axis 526 in RMS, nm. The partial pressure of the SiCl₄ in thesilicon oxide coating deposition chamber was 2.4 Torr.

FIG. 5C shows a three dimensional schematic 540 of film roughnessthickness of the silicon oxide bonding layer illustrated in FIG. 4A as afunction of the silicon tetrachloride partial pressure and the timeperiod the substrate was exposed to the coating precursors aftercompletion of addition of all precursor materials. The time period ofexposure is shown on axis 542 in minutes, with the SiCl₄ partialpressure shown on axis 544 in Torr, and the surface roughness of thesilicon oxide layer shown on axis 546 in RMS, nm. The partial pressureof the H₂O in the silicon oxide coating deposition chamber was 7.0 Torr.

A comparison of FIGS. 5A-5C makes it clear that it is the partialpressure of the H₂O which must be more carefully controlled in order toensure that the desired roughness of the coating surface is obtained.

FIG. 6 shows a graph 600, which illustrates the relationship between thehydrophobicity obtained on the surface of a SAM layer deposited fromperfluorodecyltrichlorosilane (FDTS), as a function of the thickness ofan oxide-based layer over which the FDTS layer was deposited. The oxidelayer was deposited in the manner described above, usingtetrachlorosilane precursor, with sufficient moisture that a siliconoxide surface having sufficient hydroxyl groups present to provide asurface contact angle (with a DI water droplet) of 5 degrees wasproduced.

The oxide-based layer and the organic-based layer generated from an FDTSprecursor were deposited as follows: The process chamber was vented andthe substrate was loaded into the chamber. Prior to deposition of theoxide-based layer, the surface of the substrate was plasma cleaned toeliminate residual surface contamination and to oxygenate/hydroxylatethe substrate. The chamber was pumped down to a pressure in the range ofabout 30 mTorr or less. The substrate surface was then plasma treatedusing a low density, non-physically-bombarding plasma which was createdexternally from a plasma source gas containing oxygen. The plasma wascreated in an external chamber which is a high efficiency inductivelycoupled plasma generator, and was fed into the substrate processingchamber. The plasma treatment was in the manner previously describedherein, where the processing chamber pressure during plasma treatmentwas in the range of about 0.5 Torr, the temperature in the processingchamber was about 35° C., and the duration of substrate exposure to theplasma was about 5 minutes.

After plasma treatment, the processing chamber was pumped down to apressure in the range of about 30 mTorr or less to evacuate remainingoxygen species. Optionally, processing chamber may be purged withnitrogen up to a pressure of about 10 Torr to about 20 Torr and thenpumped down to the pressure in the range of about 30 mTorr. An adheringoxide-based layer was then deposited on the substrate surface. Thethickness of the oxide-based layer depended on the substrate material,as previously discussed. SiCl₄ vapor was injected into the processchamber at a partial pressure to provide a desired nominal oxide-basedlayer thickness. To produce an oxide-based layer thickness ranging fromabout 30 Å to about 400 Å, typically the partial pressure in the processchamber of the SiCl₄ vapor ranges from about 0.5 Torr to about 4 Torr,more typically from about 1 Torr to about 3 Torr. Typically, withinabout 10 seconds of injection of the SiCl₄ vapor, water vapor wasinjected at a specific partial pressure ratio to the SiCl₄ to form theadhering silicon-oxide based layer on the substrate. Typically thepartial pressure of the water vapor ranges from about 2 Torr to about 8Torr, and more typically from about 4 Torr to about 6 Torr. (Severalvolumes of SiCl₄ and/or several volumes of water may be injected intothe process chamber to achieve the total partial pressures desired, aspreviously described herein.) The reaction time to produce the oxidelayer may range from about 5 minutes to about 15 minutes, depending onthe processing temperature, and in the exemplary embodiments describedherein the reaction time used was about 10 minutes at about 35° C.

After deposition of the oxide-based layer, the chamber was once againpumped down to a pressure in the range of about 30 mTorr or less.Optionally, the processing chamber may be purged with nitrogen up to apressure of about 10 Torr to about 20 Torr and then pumped down to thepressure in the range of about 30 mTorr, as previously described. Theorganic-based layer deposited from an FDTS precursor was then producedby injecting FDTS into the process chamber to provide a partial pressureranging from about 30 mTorr to about 1500 mTorr, more typically rangingfrom about 100 mTorr to about 300 mTorr. The exemplary embodimentsdescribed herein were typically carried out using an FDTS partialpressure of about 150 mTorr. Within about 10 seconds after injection ofthe FDTS precursor, water vapor was injected into the process chamber toprovide a partial pressure of water vapor ranging from about 300 mTorrto about 1000 mTorr, more typically ranging from about 400 mTorr toabout 800 mTorr. The exemplary embodiments described herein weretypically carried out using a water vapor partial pressure of about 600mTorr. The reaction time for formation of the organic-based layer (aSAM) ranged from about 5 minutes to about 30 minutes, depending on theprocessing temperature, more typically from about 10 minutes to about 20minutes, and in the exemplary embodiments described herein the reactiontime used was about 15 minutes at about 35° C.

The data presented in FIG. 6 indicates that to obtain the maximumhydrophobicity at the surface of the FDTS-layer, it is not onlynecessary to have an oxide-based layer thickness which is adequate tocover the substrate surface, but it is also necessary to have a thickerlayer in some instances, depending on the substrate underlying theoxide-based layer Since the silicon oxide layer is conformal, it wouldappear that the increased thickness is not necessary to compensate forroughness, but has a basis in the chemical composition of the substrate.However, as a matter of interest, the initial roughness of the siliconwafer surface was about 0.1 RMS nm, and the initial roughness of theglass surface was about 1-2 RMS nm.

The FIG. 6 graph 600 shows the contact angle of a DI water droplet, indegrees, on axis 624, as measured for an oxide-based layer surface overdifferent substrates, as a function of the thickness of the oxide-basedlayer in Angstroms shown on axis 622. Curve 626 illustrates asilicon-oxide-based layer deposited over a single crystal silicon wafersurface. Curve 628 represents a silicon-oxide-based layer deposited overa glass surface. Curve 630 illustrates a silicon-oxide-based layerdeposited over a polystyrene surface. Curve 632 shows asilicon-oxide-based layer deposited over an acrylic surface. TheFDTS-generated SAM layer provides an upper surface containing fluorineatoms, which is generally hydrophobic in nature. The maximum contactangle provided by this fluorine-containing upper surface is about 117degrees. As illustrated in FIG. 6, this maximum contact angle,indicating an FDTS layer covering the entire substrate surface is onlyobtained when the underlying oxide-based layer also covers the entiresubstrate surface at a particular minimum thickness. There appears to beanother factor which requires a further increase in the oxide-basedlayer thickness, over and above the thickness required to fully coverthe substrate, with respect to some substrates. It appears thisadditional increase in oxide-layer thickness is necessary to fullyisolate the surface organic-based layer, a self-aligned-monolayer (SAM),from the effects of the underlying substrate. It is important to keep inmind that the thickness of the SAM deposited from the FDTS layer is onlyabout 10 Å to about 20 Å.

The stability of the deposited SAM organic-based layers can be increasedby baking for about one half hour at 110° C., to crosslink theorganic-based layers. Baking of a single pair of layers is not adequateto provide the stability which is observed for the multilayeredstructure, but baking can even further improve the performance of themultilayered structure.

The integrated method for creating a multilayered structure of the kinddescribed above includes: Treatment of the substrate surface to removecontaminants and to provide either —OH or halogen moieties on thesubstrate surface, typically the contaminants are removed using a lowdensity oxygen plasma, or ozone, or ultra violet (UV) treatment of thesubstrate surface. The —OH or halogen moieties are commonly provided bydeposition of an oxide-based layer in the manner previously describedherein. At least one SAM or other functional organic layer is then vapordeposited over the oxide-based layer surface.

It is also possible to apply a hydrophobic exterior layer to a golf ballsurface using an amine-functionalized perfluoro organic precursor. Anexample precursor isicosakaihena-fluoro-1,1,2,2-tetrahydro-dodecyl-(tris-dimethylamino)silane. A tris-amine provides excellent bonding directly to the golfball surface, without the need for an oxide bonding layer. Fourinjections of the precursor from a 300 cc reservoir, where the reservoirpressure was 250 mTorr per injection was used. A reaction time of about15 minutes at about 35° C. provided an excellent hydrophobic exteriorcoating.

The above described exemplary embodiments are not intended to limit thescope of the present invention, as one skilled in the art can, in viewof the present disclosure expand such embodiments to correspond with thesubject matter of the invention claimed below.

1. An exterior coating for a golf ball which renders the exteriorsurface of said golf ball hydrophobic or hydrophilic, wherein saidcoating thickness is uniform over said golf ball surface within ±2 nm.2. An exterior coating for a golf ball in accordance with claim 1,wherein said coating provides a hydrophobic surface on said golf ball.3. An exterior coating for a golf ball in accordance with claim 2,wherein said coating includes at least two layers, where the interiorlayer in contact with the golf ball cover layer is an oxide bondinglayer, and the exterior layer, which forms an exterior surface of thecoating is an organic-comprising hydrophobic layer.
 4. An exteriorcoating for a golf ball in accordance with claim 2, wherein said coatingis a single organic layer, where the organic layer was generated from aprecursor comprising at least one amine-functionalized terminal groupand fluorine-containing terminal groups, where the at least oneamine-functionalized terminal group was reacted with the golf ball coverlayer and wherein the fluorine-containing groups are presented on anexterior surface of the golf ball.
 5. An exterior coating for a golfball in accordance with claim 3, wherein said exterior hydrophobic layerpresents fluorine atoms at the surface of the golf ball.
 6. An exteriorcoating for a golf ball in accordance with claim 3, wherein saidexterior coating exhibits a surface roughness ranging from about 3 nmRMS to about 16 nm RMS.
 7. An exterior coating for a golf ball inaccordance with claim 3 or claim 4, wherein said exterior coatingoverall thickness ranges from about 1.5 nm to about 500 nm.
 8. Anexterior coating for a golf ball in accordance with claim 3 or claim 4,wherein said exterior layer is formed from a SAM.
 9. An exterior coatingfor a golf ball in accordance with claim 2, wherein said water contactangle ranges from about 100° to about 125°.
 10. An exterior coating fora golf ball in accordance with claim 1, or claim 2, or claim 3, or claim4, applied over a golf cover layer surface comprising a polymer selectedfrom the group consisting of ionomers, polystyrene, polybutadiene,isoprene, polyurea, polyurethane, poly-para-xylene,poly-chloro-para-xylene, poly-dichloro-para-xylene, polyvinylidenechloride, polyvinylchloride, polyvinylchloride, polyacrylonitrile,fluorohalocarbons, fluorinated ethylene propylene copolymer,polytetrafluoroethylene, polyvanilidine fluoride, polyvinyl fluoride,perfluoroalkoxy resins, polyethylene, polyethylene terephthalate,polypropylene high density polyethylene, polyimide, polyamide, acrylic,and combinations thereof.
 11. An exterior coating for a golf ball inaccordance claim 1, wherein said coating provides a hydrophilic surfaceon said golf ball.
 12. An exterior coating for a golf ball in accordancewith claim 11, wherein said coating comprises an oxide layer.
 13. Anexterior coating for a golf ball in accordance with claim 12, whereinsaid coating is an oxide layer.
 14. An exterior coating for a golf ballin accordance with claim 13, wherein said coating thickness ranges fromabout 15 nm to about 500 nm.
 15. An exterior coating for a golf ball inaccordance with claim 14, wherein said exterior coating surfaceroughness ranges from about 1 nm RMS to about 10 nm RMS.
 16. An exteriorcoating for a golf ball in accordance with claim 12, wherein saidcoating also includes an organic layer which is bonded to said oxidelayer and which presents a hydrophilic exterior surface.
 17. An exteriorcoating for a golf ball in accordance with claim 16, wherein saidorganic layer comprises PEG.
 18. An exterior coating for a golf ball inaccordance with claim 17, wherein said exterior coating exhibits asurface roughness ranging from about 3 nm RMS to about 16 nm RMS.
 19. Anexterior coating for a golf ball in accordance with claim 16, whereinsaid organic layer thickness ranges from about 1.5 nm to about 25 nm.20. An exterior coating for a golf ball in accordance with claim 16,wherein said organic layer is formed from a SAM.
 21. An exterior coatingfor a golf ball in accordance with claim 11, wherein said water contactangle ranges from about 5° to about 60°.
 22. An exterior coating for agolf ball in accordance with claim 11, or claim 12, or claim 16, appliedover a golf cover layer surface comprising a polymer selected from thegroup consisting of ionomers, polystyrene, polybutadiene, isoprene,polyurea, polyurethane, poly-para-xylene, poly-chloro-para-xylene,poly-dichloro-para-xylene, polyvinylidene chloride, polyvinylchloride,polyvinylchloride, polyacrylonitrile, fluorohalocarbons, fluorinatedethylene propylene copolymer, polytetrafluoroethylene, polyvanilidinefluoride, polyvinyl fluoride, perfluoroalkoxy resins, polyethylene,polyethylene terephthalate, polypropylene high density polyethylene,polyimide, polyamide, acrylic, and combinations thereof.
 23. A method ofapplying an exterior coating over a golf ball surface, wherein saidexterior coating is deposited using vapor deposition.
 24. A method inaccordance with claim 23, wherein said exterior coating is deposited tohave a thickness ranging from about 2 nm to about 2,000 nm.
 25. A methodin accordance with claim 23, wherein said exterior coating includes atleast two vapor deposited layers, wherein the interior layer in contactwith the golf ball cover layer is a vapor deposited oxide bonding layer,and the exterior layer which makes up the exterior surface of thecoating is a vapor deposited organic-comprising layer.
 26. A method inaccordance with claim 25, wherein said vapor depositedorganic-comprising layer presents an exterior surface on the golf ballwhich is hydrophilic.
 27. A method in accordance with claim 26, whereinsaid vapor deposited organic-comprising layer presents an exteriorsurface on the golf ball which is hydrophobic.
 28. A method inaccordance with claim 23, wherein prior to vapor deposition of saidexterior coating, a surface of said golf ball to which the exteriorcoating is to be applied is treated with an oxygen-comprising plasma.